Extremity swelling is a common entity afflicting a large population worldwide. One common cause of extremity swelling is a buildup of excess fluid in the tissue of the extremity. This buildup of excess fluid is referred to generally as edema, and frequently results from an increase in capillary permeability that leads to a stasis of extravascular fluid in the extremity. The increase in fluid extravasation may manifest with dolor (pain), calor (heat), hyperemia, decreased range of motion, and/or swelling. Chronic extremity swelling can have deleterious implications on the healthy maintenance of the surrounding soft tissues and lead to skin break down and ulcers, an ulcer being defined generally as a defect in the skin, often below the knee, that has been present for more than four to six weeks. Such health implications can create significant ongoing economic burdens on a global scale.
Edema may be attributable to multiple pathologies. Two common but not exhaustive sources of edema in the lower extremities are chronic venous insufficiency (CVI) and chronic lymphedema. By clinical definition, CVI results when the venous system of the body can no longer effectively pump blood back to the heart, or otherwise from a disruption in the venous system of blood return to the heart. With respect to the lower extremities, the venous flow travels through three systems or the deep, superficial and communicating venous systems. Blood is moved upwards from the leg to the heart by muscle contraction, such as contractions of the gastrocnemius and soleus muscles of the leg. As a result of gravity, pressures change along the course of the leg when in a standing position. For example, standing pressures at the ankle are usually 90-100 mmHg in the venous system. When walking, the pressures fall quickly to around 20 mmHg but return to normal higher pressures within seconds of movement cessation.
An inability of the body to create such a pressure difference is known as venous hypertension. Venous hypertension leads to the distension of the capillary walls and leakage of various macromolecules from within the capillaries into the dermis. This leads to lipodermosclerosis or the characteristic ‘woody’ and ‘bruised’ appearance to the skin, and may ultimately result in the development of ulcers in the skin and even cell death.
Lymphedema results when lymphatic system is unable to recollect interstitial fluid that has escaped the intravascular space. The most common cause of lymphedema worldwide is the Filarioidea round worm parasite, which causes a condition known as filariasis. Other conditions such as congenital deformities, obesity, and radiation can also lead to lymphedema through lymph outflow compromise.
The lymphatic system, among other things, helps to reduce overall pressure in the lower extremities. More particularly, small lymphatic channels similar to veins capture extravasated fluid produced during inflammation and filter the fluid through lymph nodes before returning it to the general body circulation near the heart.
Damage to the valves in this system or chronic inflammation may lead to fluid accumulation in the effected extremity, with an inability to passively reabsorb such fluid. Inflammation leads to changes within the vascular structures, possibly leading to vessel dilation and cellular death.
It is estimated that CVI leading to lower extremity ulceration has an incidence of 1-4.3% of the Western population, and that 3-4% of individuals over the age of 65 manage chronic wounds of the lower extremity attributable directly to swelling and edema. Another report states that the incidence of these problems is as high as 1.2-11.0 persons per 1,000 population. Chronic skin related wounds in the United States affect over 6.5 million people each year.
The actual prevalence of such problems is much higher than indicated above, as the average duration of healing time for ulceration from CVI is reported to be over 12 months. It has also been determined that persons who develop ulcerations from CVI will experience more than ten episodes of such ulceration in his or her lifetime. The 12-month recurrence rate has been estimated to be between 18-28%, with the overall 5-year recurrence rate as high as 78% in this population.
It is estimated that lymphedema disfigures and incapacitates over 120 million people worldwide. More specifically, and as an example, it has been reported that there are between 3-5 million people in the United States affected by lymphedema, approximately 40 million in Brazil and Haiti, and around 300,000 in Canada.
Various neuropathies leading to decreased limb mobility and increased risk for inflammation or swelling also exist. One such exemplary neuropathy is Diabetes Mellitus. There are an estimated 347 million people worldwide with type II Diabetes.
Inflammatory disorders such as rheumatologic diseases or pyoderma gangrenosum can also lead to lower extremity skin problems and edema. Obesity is recognized as effecting 78 million people in the United States without an established incidence of associated lymphedema. Pregnancy is associated with silent thrombosis and increased overall intravascular fluid volumes leading to similar clinical symptoms. Extremity trauma has a high positive correlation to phlebitis and venous thrombosis. Lastly, the geriatric population, in general, has higher rates of immobility, decreased pump and muscle function and dependent lower extremity edema as a consequence.
Skin breakdown and ulceration from the above processes are common. Multiple cycles of healing and repeated ulceration comes with a recurrence rate as high 72%. It is common to see related ulcers in patients lasting over 5 years and labeled as refractory to conventional therapies.
Furthermore, the psychological effects of extremity edema, ulceration and lymphedema are detrimental to the overall quality of life. Psychological distress leading to anxiety, depression and mood disturbances is well documented and contributes to significant extraneous health care costs. There is also an associated public fear, general stigma and perceived marginalization, all of which may lead to social isolation, societal withdrawal and ultimately decreased functional work and productivity. Moreover, lack of social support and correlation to concomitant lack of health care further drives up costs.
With respect to costs, chronic wound care in the United States alone is estimated to cost over 25 billion dollars. The average monthly cost for an American with an open wound is $4,095. Of the aforementioned 25 billion dollar amount, the treatment of chronic venous ulcer wounds alone is believed to cost approximately 1-2 billion dollars, with the direct cost of treating each patient amounting to approximately $30,000 per year in the United States. Worldwide, CVI and venous ulcers leads to expenditures of over 7 billion per year in health care costs.
The treatment and management of edema, lymphedema or any other cause of increased extravascular fluid extravasation or tissue compromise in an extremity is usually initially approached through extremity elevation. The recommended anecdotal guidelines involve raising legs or arms above the heart level for 30 minutes, three to four times a day. As a result, swelling normally subsides over extended periods of time and general microcirculation improves. However, and as should be apparent, a treatment program consisting of such extremity elevation is not always practical.
The next minimally invasive approach to the treatment of such extremity problems involves compression through bandages, garments, or hosiery. The classification system used to describe this modality depends on the clinical scenario and the associated level of pressure being applied by the compression article.
Hosiery or compression stockings and other garments, commonly known as Ted Hose, involve compression through 1 or 2 layers. In the case of a leg, Class 1 garments involve light support and provide 14-17 mmHg of pressure at the ankle. Class 1 garments are used to treat varicose veins. Class 2 garments provide medium support, and produce pressures of 18-24 mmHg at the ankle. This class of garments is used to treat more severe varicosities, and to prevent venous leg ulcers. Class 3 garments provide strong support, or 25 to 35 mmHg of pressure at the ankle. This class of garments is used to treat severe chronic hypertension and severe varicose veins, and to prevent venous leg ulcers.
A parallel therapeutic intervention involves the use of long stretch elastic bandages or spiral wraps. Note that the terms bandage(s) and wrap(s) are generally used interchangeably by the medical profession (the terminology of choice depending mostly on geography) and, therefore, both terms may be used interchangeably herein and both terms are considered to refer generally to any spirally or otherwise wrapped compression device for providing multilayered compression of a limb. The term “bandage”, when used herein, is not to be construed in a narrower sense as limited to the treatment of a wound.
Multilayered compression bandages also have a grading system. Class 1 bandages are known as retention bandages, and are used to retain dressings. Class 2 bandages are known as support bandages, and are used to support strains and sprains (e.g., an Ace™ wrap). Other bandages in this category (e.g., the Setocrepe bandage from Mölnlycke) can apply mild to moderate compression. Class 3a is subcategorized as light compression. Bandages in Class 3a (e.g., the Elset bandage from Mölnlycke) exert 14 to 17 mmHg of pressure at the ankle when applied in a simple spiral. Class 3b bandages apply moderate compression. Bandages in Class 3b (e.g., the Granuflex® adhesive compression bandage from ConvaTec) apply 18 to 24 mmHg of pressure at the ankle when applied as a simple spiral. Class 3c bandages are defined as generating high compression. Bandages in Class 3c (e.g., the Setopress bandage from Mölnlycke or the Tensopress bandage from Smith and Nephew) apply 25 to 35 mmHg of pressure at the ankle when applied as a simple spiral. Lastly, Class 3d bandages deliver extra high compression. Bandages in Class 3d apply up to 60 mmHg of pressure at the ankle when applied as a simple spiral.
Yet another category of bandages includes the rigid or short stretch bandages which, when used on a leg, are designed to provide sustained pressures of 40 to 45 mm Hg at the ankle, graduating to 17 mm Hg below the knee. Pneumatic compression is another non-invasive intervention that is gaining greater acceptance for use in the improvement of lower extremity circulation, and is most often used to prevent deep venous thrombosis in incarcerated or immobile patients. In pneumatic compression, a pump actively creates air pressure to mechanically force the fluids of the extremity in a particular direction.
Ultimately, the four-layer multi-component compression bandage system (four-layer bandage) is still regarded as the gold standard initial compression system to treat venous leg ulceration and lower extremity edema. It has been found that compression increases ulcer-healing rates. Compression alone is superior to a moist interactive dressing without compression. High compression regimens are more effective than low compression. Lastly, adherence to high levels of compression after healing reduces the rate of recurrence.
It can be understood from the foregoing observations that limb swelling due to CVI, lymphedema, etc., as well as the problematic conditions that may result therefrom, is prevalent, costly, and may be extremely debilitating. While compression bandages and their use are known and accepted for the treatment of swelling, improvements therein are need to optimize treatment success and to minimize or prevent injuries that may be caused by the improper application of compression bandages. Exemplary devices and methods of this application embody such improvements.